Material anti-segregation curtain for a paver

ABSTRACT

An anti-segregation device ( 10 ) for preventing segregation of paving material (P) that is applied to a road bed ( 7 ) by a paving vehicle ( 1 ). The anti-segregation device ( 10 ) includes a first end ( 14 ) that is connected with the frame ( 2 of the paving vehicle ( 1 ) and an opposing end ( 16 ) proximal to the road bed ( 7 ). The anti-segregation device ( 10 ) is configured to substantially contain paving material (P) between the anti-segregation device ( 10 ) and a screed ( 3 ) on the paving vehicle ( 1 ). The anti-segregation device ( 10 ) substantially prevents larger material particles from falling, rolling or otherwise moving forwardly from the remainder of the paving material head (H) so as to generally prevent material segregation.

This application claims the benefit of provisional application Ser. No.60/218,987 filed Jul. 17, 2000

BACKGROUND OF THE INVENTION

The present invention relates to paving vehicles, and more particularly,to paving vehicles having screeds and devices, such as augers, forspreading paving material forwardly of the screeds.

Referring to FIG. 1, a paver vehicle or “paver” 1 generally includes apaver chassis or tractor 2 and a screed 3 for leveling paving materialand connected with the chassis 2 so as to be pulled from the rear end 2b thereof. A storage bin or hopper 4 for holding a supply of pavingmaterial P is typically mounted on the front end 2 a of the chassis 2and a conveyor 6, which extends longitudinally on the chassis 2,transports paving material P from the hopper 4 to the rear end 2 b ofthe chassis 2. The material P falls off the chassis rear end 2 b anddeposits onto a base surface 7 being paved, such as a roadbed.

An auger 8 is generally disposed between the rear end 2 b of the chassis2 and the screed 3 and functions to spread deposited material laterallyacross the front 3 a of the screed 3 so as to form a head of material H.The screed 3 is pulled into the head of material H as the paver 1travels upon the base surface 7 such that portions of the material headH flows under the screed 3 and is leveled, and preferably alsocompressed, into a mat of material M having a generally uniformthickness. Typically, the paving material P, such as asphalt or cement,is formed of an aggregate of material particles of various sizes andthere are generally substantial size differences between the larger andsmaller particles.

One problem with such known pavers arises due to the above-noted sizedifferences between the material particles of the head of material H.Larger particles, particularly those particles at the top of thematerial head H, tend to fall from the head of material H as the pavingmaterial P is first deposited and then spread by the auger 8, such thatthe head H “segregates” or separates into regions of larger particlesand smaller particles. The segregation of material particles isincreased by the forward movement of the material head H, the head Hbeing pushed along the base surface 7 by the screed 3, such that largerparticles tend to accumulate forwardly of the remainder of the head H.With such material segregation, the portions of the material head H thatare leveled tend to have a greater than intended proportion of smalleror finer particles, causing the formed material mat M to have lessstrength than desired.

Therefore, it would be desirable to provide a device for a paver toprevent the segregation of material particles in a head of pavingmaterial.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the detailed description of thepreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings, which arediagrammatic, embodiments that are presently preferred. It should beunderstood, however, that the invention is not limited to the precisearrangements and instrumentalities shown. In the drawings:

FIG. 1 is a side elevational view of a known paver, depicted engaged ina paving operation;

FIG. 2 is a side elevational view of a known paver having ananti-segregation device in accordance with the present invention,depicted engaged in a paving operation;

FIG. 3 is an enlarged, broken-away side elevational view of the paverand anti-segregation device shown in FIG. 2;

FIG. 4 is a more diagrammatic, broken-away rear perspective view of thepaver and the anti-segregation device;

FIG. 5 is a broken-away, rear elevational view of the paver and theanti-segregation device;

FIG. 6 is a broken-away rear elevational view of an adjustable augerassembly of a paver, showing one flexible curtain section; and

FIG. 7 is a side perspective view of the auger assembly and curtainsection of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in detail, wherein like numbers are usedto indicate like elements throughout, there is shown in FIGS. 2-7 ananti-segregation device 10 for preventing segregation of paving materialP applied to a base surface 7 by a paver 1 having a screed 3. Theanti-segregation device 10 basically comprises a barrier 12 having afirst end 14 connectable with the paver 1, a second, opposing end 16disposable against, or at least proximal to, the base surface 7 and aretentive surface 18 located between the first and second ends 14, 16respectively. The retentive surface 18 faces generally toward the screed3 when the first end 14 of the barrier 12 is connected with the paver 1and is configured to substantially contain paving material P between thebarrier 12 and the screed 3.

In other words, the retentive surface 18 generally prevents particles ofthe paving material P from generally separating from the material headH, and in particular, substantially prevents larger material particlesfrom falling, rolling or otherwise moving forwardly from the remainderof the material head H so as to generally prevent material segregation,such segregation being discussed above in the Background section hereof.Preferably, the barrier 12 has a sufficient length such that theretentive surface 18 extends laterally across substantially the entirewidth W of the screed 3, as discussed below.

Preferably, as shown in FIGS. 4-7, the barrier 12 is constructed as aflexible curtain 22, the curtain 22 preferably including an elongatedmounting bar 28 and a plurality of chains 20 spaced across generally thelength of the bar 28. Each chain 20 has a first end 21 attached to thebar 28 and a second, free end 23 and is formed of a plurality of links25 that each provide a separate surface portion of the retentive surface18. Thus, the retentive surface 18 of the barrier 12 is provided by thetotal of all the individual link surfaces facing generally toward thescreed 3.

Further, the individual chains 20 are spaced generally close togetheralong the bar 28 so as to provide a more continuous retentive surface18, as best shown in FIGS. 6 and 7. Alternatively, the curtain 22 may beconstructed without the bar 28, with each of the plurality of chains 20being separately and directly attached to a portion of the paver 1(e.g., chassis rear wall 34).

Preferably, each chain 20 has sufficient length such that a portion ofthe chain 20 at the lower chain end 23 is disposed upon the base surface7 when the paver chassis 2 is generally horizontal on the base surface7, as best shown in FIGS. 6 and 7. As such, if the paver 1 tiltsforwardly when traversing the base surface 7, the lower chain ends 23,collectively forming the lower end 16 of the barrier 12, remain incontact with the base surface 7 to prevent particles of paving materialfrom passing under the retentive surface 18. Further, by being formed asa flexible curtain 22 of chains 20, if the paver 1 tilts rearwardly uponthe base surface 7, such as when the chassis front end 2 a is movingupwardly over a bump or other obstruction, the lower end 16 of thebarrier 12 is able to flex or bend against the base surface 7 withoutbeing damaged.

Further, the mounting bar 28 is connectable with a portion of the paver1 so as to extend generally laterally in a direction across the width ofthe paver 1. The mounting bar 28 may be permanently affixed to a sectionof the paver 1, such as by welding, riveting, etc., or may bedemountably attached thereto, such as by using threaded fasteners,clamps, etc.

With a paver 1 having a height-adjustable, telescoping auger 8(including an auger box 30 and extendable shields 31) and/or screed endgates 27, the barrier 12 is preferably constructed of a plurality ofseparate curtain sections 26, and most preferably five curtain sections26 a, 26 b and 26 c, each having a separate mounting bar 28 and aseparate group of chains 20 and being arranged as follows. A first,central curtain section 26 a (FIG. 4) is attached to the lower end ofthe rear wall 34 of the paver chassis 2, two intermediate sections 26 bare each attached to the lower end of a separate one of the two augerboxes 30 and the auger shields 31, and two outer curtain sections 26 c(FIG. 3—one shown) are each attached to a separate one of the two endgates 27 mounted to each lateral side of the screed 3. By having such anarrangement, the barrier 12 is collectively formed of the severalcurtain sections 26 and extends across substantially the entire width ofthe screed 3 of the paver 1, and therefore across the entirelateral-extending length of the head of material H. Alternatively,particularly if the paver 1 does not have a telescoping auger(s), thebarrier 12 may be formed of only a single flexible curtain 22, or mayformed of any desired number of curtain sections 26.

Further, with the above-discussed arrangement of the barrier 12, theauger 8 is disposed generally between the anti-segregation device 10 andthe screed 3, thus containing the head of material H generally about theauger 8. However, if the paver 1 does not include an auger 8 or othersuch device for laterally distributing the paving material P, thebarrier 12 is attached to the rear wall 34 of the chassis 2, and ifappropriate, to the screed end gates 27, so as the generally contain thehead of material H between the barrier 12 and the screed 3.

Although the flexible curtain 22 is preferably formed of a plurality ofindividual chains 20, the curtain 22 may alternatively be formed fromother types of flexible strands, such as a plurality of wire cables (notshown), one or more sheets of a mesh-like material (not shown), such asfor example a section(s) of “chicken wire” or a sheet(s) ofcross-connected links, or from one or more sheets of a thin, bendablematerial (not shown).

Furthermore, the barrier 12 may even be formed of one or more generallyrigid plates (not shown) having an upper end connected with the paver 1and a lower end spaced above and proximal to the base surface 7.However, with such a barrier construction, the barrier lower end 16 isunable to flex when contacting the base surface 7 and may becomepermanently deformed, or otherwise damaged, if the paver 1 tiltsrearwardly during a paving operation.

Referring to FIGS. 2 and 3, in use, a paver 1 having an anti-segregationdevice 10, as described above, moves forwardly upon a base surface 7such that the chassis 2 pulls the screed 3 into the head of material Hand the mat M is formed thereby. The conveyor 6 continuously transportspaving material P from the hopper 4 to deposit off of the chassis 3 tobe distributed by the auger 8, such that the head of material H containsa generally consistent mass of material. The particles of the head ofmaterial H are imparted with momentum from being pushed by the forwardmoving screed 3, from contact with the rotating auger 8 and/or frombeing “flung” rearwardly off of the conveyor 6.

The particles that move generally forwardly relative to the remainder ofthe head H impact against the retentive surface 18 of the barrier 12 andare thereby generally prevented from any further relative forwardmovement. Therefore, the larger particles of paving material areprevented from separating from the material head H, such that materialsegregation is substantially prevented by the anti-segregation device10.

What is claimed is:
 1. A paving vehicle for spreading paving materialonto a road bed, the paving vehicle comprising: a frame having a frontend and a rear end; a screed for leveling the paving material, thescreed being connected with the frame so as to be pulled from the rearend of the frame and having a front surface; an auger positionedforwardly of the screed and configured to spread the paving materialalong the front surface of the screed; and an anti-segregation devicepositioned near the auger for preventing segregation of the pavingmaterial disposed on the road bed in front of the screed, theanti-segregation device including a flexible curtain having an upper endattached to the frame, a lower end contactable with the road bed and aretentive surface facing generally toward the screed, the retentivesurface being configured to generally contain the paving materialbetween the curtain and the screed, the curtain being bendable at aplurality of positions spaced vertically between the upper and lowerends of the curtain, the flexible curtain including a plurality ofchains attached to the frame of the paving vehicle.
 2. The pavingvehicle of claim 1 wherein the flexible curtain extends laterally acrosssubstantially an entire width of the screed.
 3. The paving vehicle ofclaim 1 wherein the flexible curtain includes an elongated mounting barconnected with the frame, the plurality chains being attached to andspaced across along the length of the mounting bar.
 4. The pavingvehicle of claim 3 wherein the mounting bar extends laterally across theframe of the paving vehicle.
 5. The paving vehicle of claim 3 whereineach chain includes an end attached to the mounting bar and an opposingfree end.
 6. The paving vehicle of claim 5 wherein the chains are spacedclose together along the bar so as to provide a continuous retentivesurface for the paving material.
 7. The paving vehicle of claim 1wherein each of the chains includes a lower end that is contactable withthe road bed.
 8. The paving vehicle of claim 7 wherein the lower ends ofthe chains remain in contact with the road bed when the paving vehiclemoves upwardly over an obstruction.
 9. The paving vehicle of claim 7wherein the chains are each adapted to flex against the road bed withoutbeing damaged.
 10. The paving vehicle of claim 7 wherein each chainincludes a plurality of links.
 11. The paving vehicle of claim 1 whereinthe anti-segregation device includes a plurality of separate curtainsections, each of the curtain sections being mounted to the frame by aseparate mounting bar.
 12. The paving vehicle of claim 11 wherein theplurality of curtain sections are spaced apart so as extend acrosssubstantially an entire width of the screed.
 13. The paving vehicle ofclaim 1 wherein the auger is a telescoping auger that includes a mainsection and at least one extension section and the flexible curtainextends along the entire auger.
 14. A paving vehicle for spreadingpaving material onto a road bed, the paving vehicle comprising: a framehaving a front end and a rear end; a hopper for holding a supply ofpaving material, the hopper being mounted on the front end of the frame;a conveyor which extends longitudinally on the frame and transports thepaving material from the hopper to the rear end of the frame where thepaving material falls off the rear end of the frame onto the road bed; ascreed for leveling paving material, the screed being connected with theframe so as to be pulled from the rear end of the frame; and ananti-segregation device positioned near the screed for preventingsegregation of the paving material that is positioned on the road bed infront of the screed, the anti-segregation device including a flexiblecurtain having a first end that is secured to the frame of the pavingvehicle and a second end that is proximal to the road bed, the flexiblecurtain including an elongated mounting bar that extends laterallyacross the frame and a plurality of chains spaced close together acrossalong the length of the mounting bar to provide a continuous retentivesurface for the paving material.
 15. The paving vehicle as recited inclaim 1 wherein the flexible curtain is separately bendable at aposition located proximal to the vehicle frame and at position locatedproximal to the road bed.
 16. An anti-segregation device for a pavingvehicle for spreading paving material onto a base surface, the pavingvehicle including a frame having a rear end, a screed connected with theframe so as to be pulled from the frame rear end and an auger positionedforwardly of the screed and configured for spreading paving material,the anti-segregation device comprising: a flexible curtain having afirst end connected with the paving vehicle frame, a second end disposedproximal to the base surface and a retentive surface facing generallytoward the screed, the retentive surface being configured to generallycontain the paving material between the curtain and the screed, theflexible curtain being formed of a plurality of elongated flexiblemembers connected with and spaced along the vehicle frame, each flexiblemember being one of a chain, a wire rope and a cable.